Some embodiments described herein relate generally to switch fabric systems, and, in particular, to methods and apparatus for operations, administration and management/maintenance validation within a switch fabric system.
Some known switch fabric systems include an Equal Cost Multi Path (ECMP) mechanism that provides outgoing ECMP paths from, for example, a network or an Ethernet Packet Switching Fabric switching element, as members of a single multi-chassis link aggregation group (LAG) that originate on that switching element and which individual members terminate on different downstream switching elements. In such a known switch fabric system, the traffic (e.g., data packets) can get distributed across these ECMP paths based on a LAG load distribution mechanism in the hardware of the switch fabric system. The ECMP mechanism typically includes a hashing function that operates on a set of Packet Header fields, and optionally, other values programmed or computed in the hardware datapath. In a network or switch fabric using such an ECMP mechanism, any given flow, which may also be an operations, administration and management/maintenance (OAM) mechanism (e.g., validation process), can be load-balanced to one set of ECMP paths. In such a network or switch fabric, the OAM mechanism may fail to detect forwarding failures (if any) on other paths in the network or switch fabric. Thus, such an OAM mechanism aimed at validating such a network or switch fabric may be incapable of validating all possible paths possible within the network or switch fabric.
Some known switch fabric systems include enabling next-generation OAM protocol data units (PDUs) to carry operator-specified tuples, which are fed to the LAG-based hashing mechanism. This approach implies availability of specific interfaces from the hardware that can use the given tuples as inputs for hashing. Such an approach can be impractical from a usability point of view.
Accordingly, a need exists for an OAM mechanism that can be used to validate all possible ECMP paths within a switch fabric system without having to generate OAM PDUs to probabilistically hit each of the multipaths possible within the switch fabric system.